[Federal Register Volume 66, Number 141 (Monday, July 23, 2001)]
[Proposed Rules]
[Pages 38217-38219]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-17605]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-221-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-100, -200, and -200C 
Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Boeing Model 737-100, -
200, and -200C series airplanes. This proposal would require a one-time 
inspection for damage (i.e., chafing) of the power feeder wire bundle 
for the auxiliary power unit (APU) generator and the first officer's 
elevator down control cable and for proper separation between that wire 
bundle and control cable, and corrective action, if necessary. For 
certain airplanes, this proposal also would require attaching the power 
feeder wire bundle to adjacent wire bundles. This action is necessary 
to prevent a short circuit and resultant arcing between the wire bundle 
and control cable, which could sever the control cable. Failure of the 
first officer's elevator down control cable, if combined with a 
subsequent failure of the captain's elevator down control cable, could 
result in loss of elevator control of the airplane. This action is 
intended to address the identified unsafe condition.

DATES: Comments must be received by September 6, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-221-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2001-NM-221-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Stephen Oshiro, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 227-2793; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this action may be changed in 
light of the comments received.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2001-NM-221-AD.'' The postcard will be date stamped 
and returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 2001-NM-221-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Background

    In July 1996, a Boeing Model 747 series airplane was involved in an 
accident. As part of re-examining all aspects of the service experience 
of the airplane involved in the accident, the FAA participated in 
design review and testing to determine possible sources of ignition in 
center fuel tanks. As part of the review, we examined fuel system 
wiring with regard to the possible effects that wire degradation may 
have on arc propagation.
    In 1997 in a parallel preceding, at the recommendation of the White 
House Commission on Aviation Safety and Security, the FAA expanded its 
Aging Transport Program to include non-structural systems and assembled 
a team for evaluating these systems. This team performed visual 
inspections of certain transport category airplanes for which 20 years 
or more had passed since date of manufacture. In addition, the team 
gathered information from interviews with FAA Principal Maintenance 
Inspectors and meetings with representatives of airplane manufacturers. 
This evaluation revealed

[[Page 38218]]

that the length of time in service is not the only cause of wire 
degradation; inadequate maintenance, contamination, improper repair, 
and mechanical damage are all contributing factors. From the 
compilation of this comprehensive information, we developed the Aging 
Transport Non-Structural Systems Plan to increase airplane safety by 
increasing knowledge of how non-structural systems degrade and how 
causes of degradation can be reduced.
    In 1998, an accident occurred off the coast of Nova Scotia 
involving a McDonnell Douglas Model MD-11 series airplane. 
Investigation indicates that a fire broke out in the cockpit and first 
class overhead area. Although the ignition source of the fire has not 
been determined, the FAA, in conjunction with Boeing and operators of 
Model MD-11, DC-8, DC-9, DC-10, and DC-9-80 series airplanes, is 
reviewing all aspects of the service history of those airplanes to 
identify potential unsafe conditions associated with wire degradation 
due to various contributing factors (e.g., inadequate maintenance, 
contamination, improper repair, and mechanical damage) and to take 
appropriate corrective actions. We have issued a series of 
airworthiness directives (AD) that address unsafe conditions identified 
during that process. This process is continuing and we may consider 
additional rulemaking actions as further results of the review become 
available. The cause of the Nova Scotia MD-11 accident has not yet been 
determined.
    In 1999, the FAA Administrator established a formal advisory 
committee to facilitate the implementation of the Aging Transport Non-
Structural Systems Plan. This committee, the Aging Transport Systems 
Rulemaking Advisory Committee (ATSRAC), is made up of representatives 
of airplane manufacturers, operators, user groups, aerospace and 
industry associations, and government agencies. As part of its mandate, 
ATSRAC will recommend rulemaking to increase transport category 
airplane safety in cases where solutions to safety problems connected 
to aging systems have been found and must be applied. Detailed analyses 
of certain transport category airplanes that have been removed from 
service, studies of service bulletins pertaining to certain wiring 
systems, and reviews of previously issued ADs requiring repetitive 
inspections of certain wiring systems, have resulted in valuable 
information on the cause and prevention of wire degradation due to 
various contributing factors (e.g., inadequate maintenance, 
contamination, improper repair, and mechanical damage).
    In summary, as a result of the investigations described above, the 
FAA has determined that corrective action may be necessary to minimize 
the potential hazards associated with wire degradation and related 
causal factors (e.g., inadequate maintenance, contamination, improper 
repair, and mechanical damage).

Identification of Unsafe Condition

    The FAA has received reports of chafing between the power feeder 
wire bundle for the auxiliary power unit (APU) generator and the first 
officer's elevator down control cable beneath the right side cockpit 
floor on certain Boeing Model 737-100, -200, and -200C series 
airplanes. Investigation has revealed that this problem originates when 
the power feeder wire bundle for the APU generator is not properly 
repositioned during replacement of the circuit breaker for the APU 
generator. If certain clamps on the APU generator's power feeder wire 
bundle are not loosened, the wire bundle may be pulled up or pushed 
down and may start to form a loop. If this loop chafes against the 
first officer's elevator down control cable, a short circuit and 
resultant arcing between the wire bundle and control cable could occur, 
which could sever the control cable. The resultant failure of the 
control cable may not be evident because both the captain's and first 
officer's positions have elevator control cables and both positions can 
control the elevator using either cable. However, failure of the first 
officer's elevator down control cable, if combined with a subsequent 
failure of the captain's elevator down control cable for another 
(unrelated) reason, could result in loss of elevator control of the 
airplane.

Other Related Rulemaking

    This proposed AD is one of a series of actions identified as part 
of the ATSRAC program initiative to maintain continued operational 
safety of aging non-structural systems in transport category airplanes. 
The program is continuing and the FAA may consider additional 
rulemaking actions as further results of the review become available.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Special Attention Service 
Bulletin 737-24-1144, Revision 1, dated June 21, 2001, which describes 
procedures for a one-time inspection for damage (i.e., chafing) of the 
power feeder wire bundle for the APU generator (wire bundle W146) and 
the first officer's elevator down control cable and for proper 
separation between that wire bundle and control cable. If necessary, 
corrective actions include the following:
     Replacing the first officer's elevator down control cable 
with a new cable if any damage is found.
     Repairing wire bundle W146 if any damage is found.
     Rerouting the wire bundle by turning wire bundle clamps to 
a position that provides minimum separation between the wire bundle and 
control cable, if the wire bundle and control cable are not separated 
by the minimum distance specified in the service bulletin.
    For certain airplanes, the service bulletin also describes 
procedures to attach wire bundle W146 to adjacent wire bundles.
    Accomplishment of the actions specified in the service bulletin is 
intended to address the identified unsafe condition.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require accomplishment of the actions specified in 
the service bulletin described previously, except as discussed below.

Differences Between Proposed AD and Service Bulletin

    This proposed AD differs from the service bulletin in the following 
ways:
     The service bulletin recommends that the actions be 
accomplished ``at the next normally scheduled maintenance period when 
manpower, materials, and facilities are available.'' The FAA finds that 
such a compliance time would not ensure that the identified unsafe 
condition is addressed in a timely manner. In developing an appropriate 
compliance time for this proposed AD, we considered not only the 
manufacturer's recommendation, but the degree of urgency associated 
with addressing the subject unsafe condition. In light of all relevant 
factors, we find a compliance time of 18 months after the effective 
date of the AD for completing the proposed actions is warranted, in 
that it represents an appropriate interval of time allowable for 
affected airplanes to continue to operate without compromising safety.
     The service bulletin does not specify what method to use 
for the inspection described in the Accomplishment Instructions. We 
find

[[Page 38219]]

that the procedures in the service bulletin describe a detailed visual 
inspection. A note has been included in this proposed AD to define such 
an inspection.

Cost Impact

    There are approximately 136 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 47 airplanes of U.S. registry 
would be affected by this proposed AD, that it would take approximately 
1 work hour per airplane to accomplish the proposed inspection, and 
that the average labor rate is $60 per work hour. Based on these 
figures, the cost impact of the proposed AD on U.S. operators is 
estimated to be $2,820, or $60 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the proposed requirements of 
this AD action, and that no operator would accomplish those actions in 
the future if this proposed AD were not adopted. The cost impact 
figures discussed in AD rulemaking actions represent only the time 
necessary to perform the specific actions actually required by the AD. 
These figures typically do not include incidental costs, such as the 
time required to gain access and close up, planning time, or time 
necessitated by other administrative actions.

Regulatory Impact

    The regulations proposed herein would not have a substantial direct 
effect on the States, on the relationship between the national 
Government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    For the reasons discussed above, I certify that this proposed 
regulation (1) Is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, will not have a significant economic impact, 
positive or negative, on a substantial number of small entities under 
the criteria of the Regulatory Flexibility Act. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (14 CFR part 39) as 
follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Boeing: Docket 2001-NM-221-AD.

    Applicability: Model 737-100, -200, and -200C series airplanes; 
as listed in Boeing Special Attention Service Bulletin 737-24-1144, 
Revision 1, dated June 21, 2001; certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (b) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent a short circuit and resultant arcing between the 
power feeder wire bundle for the auxiliary power unit (APU) 
generator and the first officer's elevator down control cable, which 
could sever the control cable, and, if combined with a subsequent 
failure of the captain's elevator down control cable, result in loss 
of elevator control of the airplane, accomplish the following:

Inspection and Corrective Actions

    (a) Within 18 months after the effective date of this AD, 
perform a one-time detailed visual inspection for damage (i.e., 
chafing) of the power feeder wire bundle for the APU generator (wire 
bundle W146) and the first officer's elevator down control cable and 
for proper separation between that control cable and wire bundle, 
and attach wire bundle W146 to adjacent wire bundles, as applicable. 
Do these actions according to Boeing Special Attention Service 
Bulletin 737-24-1144, Revision 1, dated June 21, 2001.

    Note 2: For the purposes of this AD, a detailed visual 
inspection is defined as: ``An intensive visual examination of a 
specific structural area, system, installation, or assembly to 
detect damage, failure, or irregularity. Available lighting is 
normally supplemented with a direct source of good lighting at 
intensity deemed appropriate by the inspector. Inspection aids such 
as mirror, magnifying lenses, etc., may be used. Surface cleaning 
and elaborate access procedures may be required.''

    (1) If no damage to the control cable or wire bundle is found, 
and if the distance between the control cable and wire bundle is 
equal to or greater than the minimum separation distance specified 
in the service bulletin: No further action is required.
    (2) If any damage to the first officer's elevator down cable is 
found: Before further flight, replace the elevator down control 
cable with a new cable according to the service bulletin, and do 
paragraph (a)(4) of this AD.
    (3) If any damage to the power feeder wire bundle for the APU 
generator (wire bundle W146) is found: Before further flight, repair 
the wire bundle according to the service bulletin, and do paragraph 
(a)(4) of this AD.
    (4) If the distance between the control cable and wire bundle is 
less than the minimum separation distance specified in the service 
bulletin: Before further flight, reroute the wire bundle by turning 
wire bundle clamps to a position that provides minimum separation 
between the wire bundle and control cable, according to the service 
bulletin.

Alternative Methods of Compliance

    (b) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Seattle Aircraft Certification 
Office (ACO), FAA. Operators shall submit their requests through an 
appropriate FAA Principal Maintenance Inspector, who may add 
comments and then send it to the Manager, Seattle ACO.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permits

    (c) Special flight permits may be issued in accordance with 
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 
21.197 and 21.199) to operate the airplane to a location where the 
requirements of this AD can be accomplished.

    Issued in Renton, Washington, on July 9, 2001.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-17605 Filed 7-20-01; 8:45 am]
BILLING CODE 4910-13-U